The present invention relates generally to an apparatus for staging or pitching articles. Specifically, the present invention relates to a conveyor table that provides a predetermined distance between adjacent articles carried on the conveyor table.
The spacing, sequencing, staging or pitching (the terms as used herein are synonymous), of articles moving along a conveyor assembly is an important task. Proper pitching of the articles reduces the tendency for the apparatus to jam. In a continuous, high throughput manufacturing operation, maintaining a predetermined distance between an article and a subsequent article is necessary so that the operations on a first article can be completed without interference from the second article. The subsequent article then must be in the proper initial position and orientation for the completion of operations on it.
To pitch the articles, conventional apparati use conveyor belts operating at different speeds. U.S. Pat. No. 3,908,333 to Cavanna typifies such a conventional apparatus. The conveyor includes several endless conveyor belts. The faster operating conveyor belts have pusher elements thereon-projections from the belt which prevent slipping of the conveyed article on the belt. The slower moving conveyor belts generally lack the pusher elements. The slower moving conveyor belts transport the articles until the pusher elements on the faster moving conveyor belt, initially trailing the article, contact a rear edge of the article. At that point, the faster moving conveyor belt captures and transports the article. The pusher elements somewhat maintain the proper pitch of the articles.
One drawback of the aforementioned device may be the misalignment caused by the pusher elements especially when multiple belts are used and become out of synchronization. As the faster moving pusher elements contact the article, the pusher elements can skew the article on the conveyor assembly. The mass of the conveyor belt and pusher elements is significantly greater than the mass of the article, creating exaggerated effects on the article when contacted by the pusher elements especially as throughput is increased. Skewing articles on the conveyor assembly can jam the apparatus or cause quality control problems.